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Supplementary Materials and Methods from Phospholipase D1 Acts through Akt/TopBP1 and RB1 to Regulate the E2F1-Dependent Apoptotic Program in Cancer Cells

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posted on 2023-03-31, 00:30 authored by Dong Woo Kang, Shin Wha Lee, Won Chan Hwang, Bo Hui Lee, Yong-Seok Choi, Young-Ah Suh, Kang-Yell Choi, Do Sik Min
<p>1. Plasmids, shRNAs and miRNA. 2. Promoter reporter constructs. 3. 3Â'UTR reporter constructs and site-directed mutagenesis. 4. Viral production and infection. 5. Reagents 6. Transient transfection and reporter gene assay. 7. Real-time quantitative PCR. 8. Quantification of mature miRNA. 9. ChIP assay. 10. mRNA microarray analysis. 11. EpiTect Methyl q-PCR Assay. 12. Mice genotype. 13. PLD activity assay. 14. In vitro limiting dilution assays (LDAs). 15. Additive statistical analysis.</p>

Funding

National Research Foundation of Korea

Translational Research Center for Protein Function Control

Ministry for Health, Welfare, and Family Affairs

Korean Health Technology R&D Project

History

ARTICLE ABSTRACT

The RB1/E2F1 signaling pathway is frequently deregulated in colorectal cancer and has been suggested to intersect with Wnt/β-catenin and PI3K/Akt pathways, but molecular evidence for this link is lacking. In this study, we demonstrate that phospholipase D1 (PLD1), a transcriptional target of β-catenin/TCF4, orchestrates functional interactions between these pathways during intestinal tumor development. Overexpression of PLD1 in intestinal epithelial cells protected cells from apoptosis induced by PLD1 ablation in the Apcmin/+ mouse model of intestinal tumorigenesis. Mechanistic investigations revealed that genetic and pharmacologic targeting of PLD1 promote the E2F1-dependent apoptotic program via both miR-192/4465–mediated downregulation of RB1 and inhibition of Akt–TopBP1 pathways. Moreover, the miRNA–RB1 axis and Akt pathway also contributed to the PLD1-mediated self-renewal capacity of colon cancer–initiating cells. Finally, PLD1-driven E2F1 target gene expression positively correlated with tumor stage in patients with colorectal cancer. Overall, our findings suggest that PLD1 mediates cross-talk between multiple major signaling pathways to promote the survival and malignancy of colon cancer cells and may therefore represent an ideal signaling node for therapeutic targeting. Cancer Res; 77(1); 142–52. ©2016 AACR.